Typical LCD display elements include a liquid crystal that is enclosed by means of an adhesive rim between two optically translucent cover plates. An electrode assembly in the form of a matrix with strip-shaped row and column electrodes is arranged on the inner sides of the two cover plates. The strip-shaped row electrodes are separated from one another by separation areas, and the strip-shaped column electrodes are separated from one another by spacing areas. The areas of intersection between row and column electrodes, together with the liquid crystal in between them, define the individual pixels of the LCD display element. The electrode material typically consists of indium tin oxide (ITO).
European patent EP1962129 A1 discloses a passive matrix liquid crystal display element with column electrodes and row leads. The row leads are routed under the adhesive rim in the plane of the column electrodes between the column electrodes towards the contacts. This allows the rim areas to be designed outside the viewing area with the same small width in the area of the left, right, and upper lateral edges. The liquid crystals used in a passive matrix liquid crystal display element are bi-stable, i.e., they possess two stable orientation conditions: reflective (ON condition) and transparent or weakly dispersive (OFF condition). In order to bring about the one or the other stable orientation condition, i.e., in order to switch a particular pixel to ON or OFF and thus bring about the data value 1 or 0, different sequences of voltage pulses for the ON condition and for the OFF condition are applied to the respective row and column electrodes. A plurality of voltage pulses is necessary to ensure stability of the respective condition, reduce switching times, and so as not to reduce the service life of the liquid crystal. In more simple terms, the liquid crystal switches over from the OFF condition to the ON condition upon reaching a particular minimum voltage between the row and column electrodes. In the case of the customarily used sequences of row and column voltage pulses, it was found that the areas of the liquid crystal situated in the areas of intersection between the respective row lead and the row electrodes extending transversely thereto are also driven. In order to avoid such crosstalk, European patent EP1962129 A1 teaches locating the electrical contact points or adhesive dots in these areas of intersection. Inadvertent driving cannot occur in the remaining areas between two column electrodes, as an electrode layer is present on one side of the liquid crystal only. Nevertheless, these small areas that cannot be influenced, or driven, in combination with the drivable pixels bring about undesirable brightness and color effects.
Considering the teachings of European patent EP1962129 A1, it is therefore the object of the present invention to design an LCD display element and an LCD display panel wherein such undesirable, optically visible effects are reduced. It is furthermore the object of the present invention to specify a corresponding method for driving such an LCD display element and LCD display panel.